Problem: Simplify the following expression: $r = \dfrac{3}{7x - 9} \times \dfrac{10x}{4}$
Solution: When multiplying fractions, we multiply the numerators and the denominators. $r = \dfrac{ 3 \times 10x } { (7x - 9) \times 4}$ $r = \dfrac{30x}{28x - 36}$ Simplify: $r = \dfrac{15x}{14x - 18}$